If there were any last doubts about how serious Roger Goodell is when it comes to protecting the image of the NFL, the commissioner dispelled them Tuesday with his stiff punishment of Indianapolis Colts owner Jim Irsay.

Within hours of Irsay pleading guilty to a misdemeanor charge of driving while impaired and getting a year's probation, Goodell imposed his own sentence: A six-game ban and $500,000 fine, the maximum allowed under league rules.

Irsay also is barred from the team's practice facility, and he cannot represent the Colts at any NFL meetings or functions.

"I have stated on numerous occasions that owners, management personnel and coaches must be held to a higher standard than players," Goodell wrote in a letter to Irsay.

Some have said Irsay's punishment should have been even harsher, eight games perhaps. Or that Irsay, a recovering alcoholic, should be subject to mandatory drug testing beyond the year ordered by the court.

After all, it was pure luck Irsay was facing only a drug charge and not bodily injury or vehicular manslaughter.

When police spotted Irsay in March, the Colts owner was driving erratically. He had trouble standing after he was pulled over, and police found several bottles of prescription drugs in his car. A toxicology report showed he had the powerful painkillers oxycodone and hydrocodone in his system.

But keep in mind that Irsay's penalty is far tougher than what a player would face. There are no suspensions for a first DUI, and a player cannot be fined more than $50,000, according to the collective bargaining agreement.

When taken with Goodell's other disciplinary measures just within the last week, it sends a clear message that he will not play favorites. Do something to make the NFL look bad and, regardless of who you are, Goodell will make you pay.

Cleveland Browns wide receiver Josh Gordon won't play this season because of repeated violations of the NFL's substance abuse policy. San Francisco 49ers linebacker Aldon Smith was suspended for nine games Friday for violations of both the league's drug and personal conduct policies.

Goodell also toughened the NFL's penalties for domestic violence after being roundly criticized for Ray Rice's ridiculously light two-game ban.

Had Goodell not taken an even firmer line with Irsay, it would have sent a message that owners are above his law, something that would not have gone over well with the players or the public.

The NFL is, by large margins, the country's favorite sport, and it has been immune to bad publicity. Even the concussion crisis, which has made players past and present worry about the toll the game will exact on them, has done little to dent the NFL's popularity.

And Goodell is determined to keep it that way, showing far less forgiveness for misconduct than his predecessors.

He has little tolerance for players who don't get his message the first or second time around, as Gordon or Smith can attest. He has imposed almost Draconian sentences for offenses he considers particularly damaging to the NFL's image, such as the New Orleans Saints' Bountygate.

Players are, understandably, leery of his unchecked authority. There's a reason that, three years after it was agreed to, the NFL still doesn't have HGH testing.

But Goodell is making no apologies. His job is to make sure the NFL's good name remains intact, and if that means he has to play the heavy, so be it.